package com.atguigu.apitest.transform;/**
 * Copyright (c) 2018-2028 尚硅谷 All Rights Reserved
 * <p>
 * Project: FlinkTutorial
 * Package: com.atguigu.apitest.transform
 * Version: 1.0
 * <p>
 * Created by wushengran on 2020/11/7 15:39
 */

import com.atguigu.apitest.beans.SensorReading;
import org.apache.flink.api.common.functions.ReduceFunction;
import org.apache.flink.api.java.tuple.Tuple;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.datastream.KeyedStream;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;

/**
 * @ClassName: TransformTest3_Reduce
 * @Description:
 * @Author: wushengran on 2020/11/7 15:39
 * @Version: 1.0
 */
public class TransformTest3_Reduce {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);

        // 从文件读取数据
        DataStream<String> inputStream = env.readTextFile("D:\\Projects\\BigData\\FlinkTutorial\\src\\main\\resources\\sensor.txt");

        // 转换成SensorReading类型
        DataStream<SensorReading> dataStream = inputStream.map(line -> {
            String[] fields = line.split(",");
            return new SensorReading(fields[0], new Long(fields[1]), new Double(fields[2]));
        });

        // 分组
        KeyedStream<SensorReading, Tuple> keyedStream = dataStream.keyBy("id");

        // reduce聚合，取最大的温度值，以及当前最新的时间戳
        SingleOutputStreamOperator<SensorReading> resultStream = keyedStream.reduce(new ReduceFunction<SensorReading>() {
            @Override
            public SensorReading reduce(SensorReading value1, SensorReading value2) throws Exception {
                return new SensorReading(value1.getId(), value2.getTimestamp(), Math.max(value1.getTemperature(), value2.getTemperature()));
            }
        });

        keyedStream.reduce( (curState, newData) -> {
            return new SensorReading(curState.getId(), newData.getTimestamp(), Math.max(curState.getTemperature(), newData.getTemperature()));
        });

        resultStream.print();
        env.execute();
    }
}
